Thanks for the replies. Anecdotally I'm definitely inclined to agree, though I question if things are less "efficient" just because the body is over a certain BF%, at least in and of itself. I vaguely seeing the idea tossed about as a given in some articles or threads I've read in the past and it happens to be an issue of recent interest to me.
As Derek mentioned, early CF readings may have first planted the bug, but I am really thinking of something I saw since then that cited very specific BF% range (for males IIRC) - something like 10-18%, outside of which things didn't work as well in either direction. I would think that if this research had any credibility or real thorough backing, we'd see implementation of the theory in top level sports that have weight classes. Then again, I've seen some articles on aggressive weight-cutting being extremely deleterious of performance, but that is still done aggressively in sports to success, so it must really depend.
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